The present invention relates to applicator and to coaters of the type used to deposit a layer or layers of liquid onto an object such as a web or a sheet.
Various types of applicators are known in the art and are used to deposit layers of liquid onto objects. One type of applicator is known as a slot applicator and is used to deposit a thin layer of liquid over a wide area. Examples of such applicators are shown in U.S. Pat. No. 5,851,289, entitled xe2x80x9cAPPLICATORxe2x80x9d, which issued Dec. 22, 1998 to Sony Corporation and U.S. Pat. No. 2,761,791, entitled xe2x80x9cMETHOD OF MULTIPLE COATINGxe2x80x9d which issued Sep. 4, 1956. These types of applicators are used to deposit layers of coatings in the production of magnetic tapes, adhesive tapes, photographic materials and paper, for example.
Typically, prior art slot applicators must be specially designed for the type of liquid which they will dispense and the particular relationship between the applicator and the substrate. Thus, it is frequently not possible to use a single applicator for more than one particular application. Applicators tend to be limited to a particular liquid and a particular substrate configuration. This also makes maintaining, reconfiguring or replacing applicators difficult, time consuming and expensive.
An applicator includes a slot and a reservoir which extends from the slot and has a shape which generally conforms to the slot. The reservoir is configured to contain a liquid therein. A piston which conforms to the reservoir is configured to move in the reservoir to thereby urge the liquid in the reservoir toward the slot.